Different oncogenes were transfected into GYB33 cells. TBE-1 is a cell line established in our laboratory that represents Harvey ras-transfected human normal epithelial cells. TBE-1 cells have an extended lifespan and can be considered as immortal. These cells, however, do not induce tumors in nude mice. TBE-1 cells were stably transfected with the v-myc oncogene. The ability of these cells to form tumors in nude mice is now being investigated. GBY33 cells passed through soft agar were also transfected with raf, raf/myc, and Burkitt's myc oncogenes.